This longitudinal, developmental follow-up study has four general objectives: First, to establish at multiple points in time through 10 years of age the developmental outcome of VLBW in terms of medical, cognitive, neuromotor, communication and psychosocial dimension of the child's functioning and impact on parents and family. Second, to delineate perinatal biological and psychosocial risk status. Third, to assess two sets of the variables likely to mediate risk status and outcome: control factors, i.e. demographic and environmental factors likely to influence developmental outcome (e.g. sex, race, maternal intelligence and quality of social, emotional and cognitive support in the home) and the roles of parental cognitive processes, coping responses, and social support in effective coping. Fourth, to provide the integrating framework to assess how biological and psychosocial processes, that are the focus of the component studies comprising this project, act together to mediate between early biological risk and subsequent outcome in VLBW infants. Particular attention is directed toward the identification of factors and processes associated with movement into or out of at-risk status. This study utilizes a systems theory perspective and a biopsychosocial transactional model. Premature birth with VLBW is viewed as a stressful condition with associated biological and psychosocial risks. Developmental outcome is multidimensional and is a function of biological risk factors, psychosocial risk factors, and their interaction and of mediational factors. The mutual influence, and change over time, of characteristics of the infants, parents, family, and environment are the mediational factors. Developmental processes are emphasized as opposed to static factors. The long term objectives of this study are not just to delineate the impact of VLBW nor to delineate biological and psychosocial risk markers but to provide the knowledge base necessary to develop an efficient health care system for vulnerable infants that would enable identification of infants and families who are at risk for subsequent developmental and psychosocial problems and specificity of intervention and prevention efforts.